In order to prevent damage to the north bridge abutment by the tunnelling machine, the whole of the ground beneath the bridge had to be replaced with a weak concrete by constructing interlocking 1200mm diameter piles to 13.0m within a headroom constraint of 5.1m.

The Martello Solution

In just 6 weeks, Martello re-designed and modified 2 of their MP5000 series rigs to meet the client's required start date, and to enable them to operate in 5.1m of headroom by manufacturing new short masts, multi-stage digging bars and very short digging tools.

The mass concrete protection of the bridge abutment consisted of 418 No 1200, 900 & 600mm diameter piles 13m deep, that were installed using the modified MP5000 rigs.

The 56 No 900mm contiguous piles installed to form a portal structure on the East bound running tunnels. These were installed using the MP4000 rig with full depth B40 reinforcement in short lengths with coupled connections.

Martello worked extended hours to deliver the works ahead of time and on budget.

Future Potential

Martello Piling have the culture, the creativity and the in-house capability to design and manufacture bespoke equipment to solve ground engineering problems which may not be possible with conventional piling equipment.